Air fresheners are conventionally used to provide a desired fragrance to ambient air, or to mask, neutralize or counteract undesirable odors in the air, or to achieve a combination of these functions.
Many liquid air fresheners are commercially available in different formats such as reed or wick diffusers, electrical plug-in devices, aerosols, or sprays (see, e.g., U.S. Pat. No. 6,180,595; U.S. Patent Publication No. 2008/0023569, and U.S. Patent Publication No. 2011/0095097. The perfume composition of the air freshener may be a fragrance concentrate, a true solution, or a colloidal solution such as a microemulsion. However, conventional liquid air fresheners often suffer from certain disadvantages and limitations. For example, air freshener performance may be unsatisfactory due to limited or even unacceptable fragrance performance, product longevity, esthetical appearance, or temperature product stability over time. Certain air fresheners include high levels of volatile organic compound (VOC) solvents, which are disfavored due to environmental and safety concern, and may raise regulatory concerns.
Also, many conventional air freshener formulations, including aqueous-based formulations, impose restrictions in fragrance creativity and limitations on the level of fragrance that can be employed due to fragrance solubility or solubilization issues. For example, perfumed liquid air fresheners containing high level of water often require large amounts of solubilizers, such as surfactants, in order to achieve the desired clarity and stability of the final products. Such products may contain excess amounts of solubilizers with respect to the perfume; sometimes the weight ratio of surfactant to perfume is at least 1.5:1 or even higher, which may have unsatisfactory impact on fragrance performance over time, such as fragrance release and fragrance perception (intensity, character, and the like). The use of high levels of solubilizers can lead to unacceptable product performance, such as limited performance over time due to suppressed or poor fragrance release through delivery device such as wicks or reeds as a result of the solubilizer clogging the capillary channels in the diffuser. Similarly, high levels of solubilizers can result in clogging of the actuator in nozzle sprays.
Therefore, there is a need for improved air freshener formulations to address these and other problems.